Preparation method of green degradable fiber mask base cloth

Abstract

The invention relates to a preparation method of green degradable fiber mask base cloth, and relates to the technical field of bio-based material and green cosmetic manufacturing, and the green degradable fiber mask base cloth comprises the following components: 38-42% of sodium alginate; 28 to 32% of nano cellulose; 1-3% of carboxylated sodium lignin sulfonate; the deep eutectic solvent is composed of choline chloride and glycerin according to the mass ratio of 1: 3; 4-6% of CaCO3 nano-particles, the particle size of the CaCO3 nano-particles is 18-22 nm, and the CaCO3 nano-particles can release Ca < 2 + > under the condition that the pH value is less than or equal to 6; the diameter of the nano cellulose is 10-20 nm, and the nano cellulose is prepared by pretreating straw with 1.5-2.5% H2SO4 and then hydrolyzing the pretreated straw with 40-60 U / g cellulase at 35-45 DEG C for 20-28 h; the nano cellulose is subjected to high-pressure homogenization treatment for 15 to 25 times under the pressure of 45 to 55 MPa. The full-component environment-friendly degradable micro-plastic material is green and degradable, and micro-plastic pollution is eliminated; the durability of the product is improved through the dynamic self-repairing function; a bionic topological structure breaks the tough-degradation contradiction; no chemical cross-linking process is used for guaranteeing the activity and safety of the components.

Description

Technical Field

[0001] The present application relates to the technical field of bio-based materials and green cosmetics manufacturing, and in particular to a method for preparing a green and degradable fiber mask base cloth. Background Art

[0002] Currently, mainstream facial mask fabrics are based on petroleum-based synthetic fibers. Their production chain is deeply dependent on non-renewable resources, and environmentally toxic substances such as plasticizers and formaldehyde cross-linkers need to be added during the spinning process. These ingredients not only lead to microplastic pollution that can last for centuries after the product is discarded, but the residual free formaldehyde and phthalates also pose allergic and carcinogenic risks, seriously deviating from the "clean beauty" development trend of the cosmetics industry. Even more seriously, the organic solvents used in traditional processes (such as DMF and DMSO) are difficult to recycle due to their high boiling points and strong biological toxicity, generating tens of thousands of tons of toxic wastewater each year. The cost of treating them accounts for more than 30% of the production cost, becoming a core pain point that restricts the green upgrade of enterprises.

[0003] Regarding the above-mentioned related technologies, bio-based alternatives represented by calcium alginate are available. However, its static ion cross-linked network is prone to calcium ion loss in a wet environment, resulting in a decrease in tensile strength of more than 60% after the fiber membrane absorbs water and expands, which cannot meet the mechanical requirements of the mask base fabric for repeated folding and wet use. At the same time, existing technologies often excessively weaken the stability of the material in order to increase the degradation rate, causing the product to show obvious aging and brittle cracking during the shelf life, forming a binary opposition dilemma of "environmental protection-practicality". In terms of functional expansion, traditional post-finishing processes rely on chemical cross-linking agents to fix active ingredients, which not only causes an ingredient inactivation rate of up to 40%, but also causes the active ingredients to degrade prematurely during the storage period due to the lack of an intelligent release mechanism, ultimately causing the product to fall into a market trust crisis of "high claims and low performance". Summary of the Invention

[0004] The purpose of this application is to provide a method for preparing a green and degradable fiber mask base cloth.

[0005] In the first aspect, the present application provides a green biodegradable fiber mask base fabric adopts the following technical solution: comprising the following components: Sodium alginate: 38-42%; Nanocellulose: 28-32%; Carboxylated sodium lignin sulfonate: 1-3%; Deep eutectic solvent: 8-12%, composed of choline chloride and glycerol in a mass ratio of 1:3; CaCO3 nanoparticles: 4-6%. The CaCO3 nanoparticles have a particle size of 18-22 nm and can release Ca2+ under pH ≤ 6.

[0006] Preferably, the nanocellulose has a diameter of 10-20 nm and is prepared by pre-treating straw with 1.5-2.5% H2SO4 and then hydrolyzing it with 40-60 U / g cellulase at 35-45°C for 20-28 hours.

[0007] Preferably, the nanocellulose is subjected to 45-55 MPa high pressure homogenization treatment for 15-25 times.

[0008] Preferably, the carboxyl content of the carboxylated sodium lignin sulfonate is 2.3-2.7 mmol / g, and ...ylated sodium lignin sulfonate is obtained by oxidizing papermaking black liquor with 8-12% H2O2 at 50-60°C for 3-5 hours and then dialysis purification.

[0009] In a second aspect, the present application provides a method for preparing a green biodegradable fiber mask base fabric using the following technical solution: comprising the following steps: (1) Dynamic spinning solution preparation: Sodium alginate, nanocellulose, carboxylated sodium lignin sulfonate and deep eutectic solvent were mixed, CaCO3 nanoparticles were added, and stirred at 55-65°C for 30-60 min; (2) Pulse shear microfluidic spinning: alternately apply 9.5×10 3 -1.05×104s-1 high shear rate for 8-12s and zero shear rate for 4-6s, cycled 3-5 times; (3) Plasma biomimetic bonding: The fiber surface is treated with nitrogen plasma and then grafted with mussel byssus protein; (4) Closed-loop solvent regeneration: recovering the deep eutectic solvent and adding waste lignin for regeneration; (5) Post-processing and functional activation: pH buffer treatment and gradient drying.

[0010] Preferably, in step (2): A microfluidic spinning head with a pore size of 45-55 μm was used to control the spinning solution flow rate to 0.8-1.2 mL / min; The spun fibers were shaped by infrared annealing at 115-125°C for 4-6 seconds.

[0011] Preferably, in step (3): The nitrogen plasma treatment power is 90-110W, the chamber pressure is 50-70Pa, and the treatment time is 25-35s; The spraying concentration of the mussel byssus protein solution is 4.5-5.5%, the spraying pressure is 0.18-0.22 MPa, and the flow rate is 4.5-5.5 mL / min.

[0012] Preferably, in step (4): A ceramic membrane with a molecular weight cutoff of 0.9-1.1 kDa was used to recover the deep eutectic solvent at 35-45 °C; During regeneration, 2.5-3.5% (w / w) waste lignin was added, stirred for 30-60 minutes and then filtered.

[0013] Preferably, in step (5): The pH buffer is a 0.08-0.12 mol / L sodium citrate system, with a pH value of 5.4-5.6 and a treatment time of 10-20 min; The first stage of gradient drying was 45-55°C for 8-12 min, and the second stage was 25-35°C for 18-22 min.

[0014] Preferably, the method for extracting sodium alginate comprises: Crush the brown algae to 0.5-1.0 mm and extract with 0.4-0.6 mol / L Na2CO3 solution at a solid-liquid ratio of 1:10 (w / v) at 45-55°C for 3-5 h; After centrifugation, ethanol precipitation, vacuum drying, purity> 95% By adopting the above technical solution, the problems of non-degradability, poor wet mechanical properties and high production pollution of facial mask base fabrics in the prior art are solved.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. This invention abandons the non-degradable petroleum-based plasticizers and formaldehyde crosslinkers in traditional facial mask base fabrics. Through the bio-based synergy of sodium alginate, nanocellulose, and sodium lignin sulfonate, a fiber network derived entirely from natural raw materials is constructed. This ensures that the facial mask base fabric can be quickly decomposed by the natural environment after use, completely solving the problem of microplastic pollution and conforming to the sustainable development trend of the cosmetics industry. 2. This invention innovatively incorporates a synergistic system of carboxylated lignin and pH-responsive CaCO3 nanoparticles. Through the coupling of dynamic coordination bonds and ionic bonds, the fiber membrane can autonomously repair microcracks when damaged by external forces. This feature significantly improves the mask base fabric's resistance to damage during transportation and folding, breaking through the limitation of traditional materials that "fail upon single damage." 3. This invention utilizes a pulsed shear-induced helical biomimetic structure design, replicating the strength and toughness of spider silk within the fiber network. This allows the mask base fabric to maintain high tensile strength while increasing its elongation at break to over three times that of conventional processes. This structure achieves a balance between mechanical performance and degradation rate through biomimetic principles, avoiding sacrificing environmental performance for strength. 4. This invention utilizes low-temperature spinning with a deep eutectic solvent and plasma biomimetic bonding technology, avoiding high-temperature treatment or the addition of chemical crosslinkers throughout the entire process. This process not only fully preserves the biological efficacy of active ingredients such as plant extracts, but also completely eliminates the risk of residual harmful substances such as formaldehyde and phthalates, meeting medical-grade biosafety requirements. 5. This invention utilizes a coupled lignin adsorption-solvent regeneration technology to transform waste liquids from traditional processes and agricultural and forestry waste into renewable resources, creating a closed-loop production chain with zero waste discharge. This system achieves a solvent recovery rate exceeding 98% while reducing raw material costs by over 30%, providing a viable solution for large-scale green manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a step diagram of the method of the embodiment of the present application. DETAILED DESCRIPTION

[0017] The following is combined with Figure 1 , further details of this application are given.

[0018] A green and biodegradable fiber mask base fabric, comprising the following components: Sodium alginate: 38-42%; Nanocellulose: 28-32%; Carboxylated sodium lignin sulfonate: 1-3%; Deep eutectic solvent: 8-12%, composed of choline chloride and glycerol in a mass ratio of 1:3; CaCO3 nanoparticles: 4-6%. The CaCO3 nanoparticles have a particle size of 18-22 nm and can release Ca2 at pH ≤ 6.

[0019] A method for preparing a green biodegradable fiber mask base fabric comprises the following steps: (1) Dynamic spinning solution preparation: Sodium alginate, nanocellulose, carboxylated sodium lignin sulfonate and deep eutectic solvent were mixed, CaCO3 nanoparticles were added, and stirred at 55-65°C for 30-60 min; (2) Pulse shear microfluidic spinning: alternately apply 9.5×10 3 -1.05×104s-1 high shear rate for 8-12s and zero shear rate for 4-6s, cycled 3-5 times; (3) Plasma biomimetic bonding: The fiber surface is treated with nitrogen plasma and then grafted with mussel byssus protein; (4) Closed-loop solvent regeneration: recovering the deep eutectic solvent and adding waste lignin for regeneration; (5) Post-processing and functional activation: pH buffer treatment and gradient drying.

[0020] Raw material pretreatment Extraction of sodium alginate Dried brown algae is crushed to a particle size of 0.5-1.0 mm, mixed with a 0.4-0.6 mol / L sodium carbonate solution at a solid-to-liquid ratio of 1:10 (w / v), and stirred continuously at 45-55°C for 3-5 hours. After centrifugation to remove the residue, 95% ethanol is slowly added to the supernatant to a final concentration of 60-70% (v / v), resulting in the precipitation of sodium alginate. Vacuum drying (40-50°C, 12-16 hours) yields a white powder with a purity >95%.

[0021] Preparation of nanocellulose Rice straw is crushed to 1-2 mm and soaked in a 1.5-2.5% sulfuric acid solution at 100-110°C for 1.5-2.5 hours to remove lignin. After washing until neutral, 40-60 U / g of cellulase is added and enzymatic hydrolysis is carried out at 35-45°C and pH 4.8-5.2 for 20-28 hours. The hydrolysis product is subjected to a high-pressure homogenizer (45-55 MPa) for 15-25 times to obtain a nanocellulose suspension with a diameter of 10-20 nm. The solids content is adjusted to 2.0-3.0% (w / w).

[0022] Preparation of Carboxylated Sodium Lignosulfonate After filtering papermaking black liquor, the pH is adjusted to 2.0-3.0 with hydrochloric acid and centrifuged to obtain crude sodium lignin sulfonate. The crude product is mixed with 8-12% (w / w) hydrogen peroxide solution at a ratio of 1:5 (w / v) and oxidized with stirring at 50-60°C for 3-5 hours. The reaction solution is dialyzed through a dialysis bag (molecular weight cut-off 1000 Da) for 48 hours and freeze-dried to obtain carboxylated sodium lignin sulfonate powder with a carboxyl group content of 2.3-2.7 mmol / g.

[0023] Dynamic spinning solution preparation Weigh the following components by mass percentage: Sodium alginate: 38-42%; Nanocellulose (solid content 2.0-3.0%): 28-32%; Carboxylated sodium lignin sulfonate: 1-3%; Deep eutectic solvent (choline chloride: glycerol = 1:1-1:3): 8-12%; Citric acid surface-modified CaCO3 nanoparticles (particle size 18-22 nm): 4-6%.

[0024] Sodium alginate, nanocellulose, and carboxylated sodium lignin sulfonate are sequentially added to a deep eutectic solvent and stirred at 200-300 rpm for 30-60 minutes at 55-65°C until a homogeneous sol is formed. CaCO3 nanoparticles are then added and stirring is continued for 10-20 minutes to form a pH-responsive, dynamically cross-linked sol system.

[0025] Pulsed shear microfluidic spinning A multi-channel microfluidic spinning head (pore size 45-55 μm) was used, and the spinning solution flow rate was controlled at 0.8-1.2 mL / min. The following shear conditions were applied alternately via a programmable controller: High shear stage: shear rate 9.5×10 3 -1.05×10 4 s -1 , lasting 8-12 seconds, inducing the nanocellulose to align along the flow direction; Zero shear stage: Standing for 4-6 seconds, the entropy elasticity of nanocellulose is used to spontaneously form a helical structure (helical angle 45°±5°).

[0026] After the above cycle is repeated 3-5 times, the fiber bundle is treated in an infrared radiation zone (wavelength 2.5-5.0 μm, temperature 115-125° C.) for 4-6 seconds to lock the helical topology.

[0027] Plasma biomimetic bonding The fiber membrane is placed in a nitrogen plasma reactor and evacuated to a chamber pressure of 50-70 Pa. A radio frequency power supply (13.56 MHz, 90-110 W) is activated for 25-35 seconds to generate active free radicals on the fiber surface. Subsequently, a 4.5-5.5% (w / w) mussel byssus protein solution (in pH 7.4 phosphate buffer) is sprayed at a pressure of 0.18-0.22 MPa, a flow rate of 4.5-5.5 mL / min, and a spray distance of 10-15 cm. This allows the catechol groups to covalently graft onto the active free radicals, forming a wet-stable bonding interface.

[0028] Closed-loop solvent regeneration and waste lignin utilization The spinning waste liquor is collected and processed through a ceramic membrane separation device (molecular weight cut-off 0.9-1.1 kDa, operating temperature 35-45°C) to recover the deep eutectic solvent (recovery rate >98%). 2.5-3.5% (w / w) waste lignin (from papermaking black liquor extract) is added to the recovered solvent and stirred at 25-30°C for 30-60 minutes. The lignin absorbs the residual alginate molecules through π-π stacking, forming a homogeneous regenerated spinning solution that is directly used for the next batch of production.

[0029] Post-processing and function activation The fiber membrane was immersed in sodium citrate buffer (concentration 0.08-0.12 mol / L) at pH 5.4-5.6 for 10-20 minutes to trigger the release of CaCO3 nanoparticles. 2+ , while dissociating lignin-Ca 2+ Dynamic bond, release pre-loaded active ingredients (such as tea polyphenols). Followed by gradient drying: The first stage: hot air drying at 45-55℃ for 8-12 minutes to quickly remove free moisture on the surface; The second stage: slow drying at 25-35℃ constant humidity (RH50-60%) for 18-22 minutes to allow moisture inside the fiber to migrate evenly and prevent curling and deformation.

[0030] Example 1 Raw material ratio and parameters Sodium alginate: 40% (extracted from 0.5 mol / L Na2CO3, 50°C x 4h) Nanocellulose: 30% (1.5% H2SO3 pretreatment for 2 hours, 50U / g enzymatic hydrolysis for 24 hours, high-pressure homogenization 20 times) Carboxylated sodium lignin sulfonate: 2% (oxidized with 10% H2O2 for 4 hours, carboxyl content 2.5 mmol / g) Deep eutectic solvent (choline chloride: glycerol = 1:2): 10% CaCO3 nanoparticles: 5% (particle size 20nm) Preparation steps Dynamic spinning solution preparation: Stir at 60°C for 45 minutes to form a homogeneous sol.

[0031] Pulse shear spinning: The microfluidic spinning head had an aperture of 50 μm and a flow rate of 1.0 mL / min.

[0032] Shear rate 1.0×10 4 s -1 Continue for 10 seconds, rest for 5 seconds, and repeat 4 times.

[0033] Infrared annealing: 120℃×5s.

[0034] Plasma treatment: Nitrogen plasma (100 W, 60 Pa × 30 s).

[0035] Spray 5% mussel protein solution at a pressure of 0.20 MPa and a spraying distance of 12 cm.

[0036] Solvent regeneration: The solvent was recovered by a ceramic membrane (cut-off 1.0 kDa) and 3% waste lignin was added.

[0037] Post-processing: Soak in pH 5.5 buffer for 15 min and then dry in a gradient manner (50°C×10 min→30°C×20 min).

[0038] Example 2 Raw material ratio and parameters Sodium alginate: 38% (0.4 mol / L Na2CO3, 45°C x 5h) Nanocellulose: 32% (2.0% H2SO3 pretreatment for 1.5h, 40U / g enzymatic hydrolysis for 28h, homogenization 15 times) Carboxylated sodium lignin sulfonate: 1% (8% H2O2 oxidation for 5h, carboxyl content 2.3mmol / g) Deep eutectic solvent (choline chloride: glycerol = 1:1): 8% CaCO3 nanoparticles: 6% (particle size 18nm) Preparation steps Dynamic spinning solution preparation: stirring at 55°C for 60 minutes.

[0039] Pulse shear spinning: Pore size 45 μm, flow rate 0.8 mL / min.

[0040] Shear rate 9.5×10 3 s -1 Continue for 12 seconds, rest for 4 seconds, and repeat 3 times.

[0041] Infrared annealing: 115℃×6s.

[0042] Plasma treatment: Power 90W, chamber pressure 50Pa×35s.

[0043] Spray 4.5% protein solution at a pressure of 0.18 MPa and a spraying distance of 15 cm.

[0044] Solvent regeneration: 2.5% lignin was added and stirred for 60 minutes.

[0045] Post-processing: The mixture was treated with pH 5.4 buffer for 20 min and then dried in a gradient manner (45°C × 12 min → 25°C × 22 min).

[0046] Example 3 Raw material ratio and parameters Sodium alginate: 42% (0.6 mol / L Na2CO3, 55°C x 3h) Nanocellulose: 28% (2.5% H2SO3 pretreatment for 2.5h, 60U / g enzymatic hydrolysis for 20h, homogenization 25 times) Carboxylated sodium lignin sulfonate: 3% (oxidized with 12% H2O2 for 3 hours, carboxyl content 2.7 mmol / g) Deep eutectic solvent (choline chloride: glycerol = 1:3): 12% CaCO3 nanoparticles: 4% (particle size 22nm) Preparation steps Dynamic spinning solution preparation: Stir at 65°C for 30 min.

[0047] Pulse shear spinning: Pore size 55 μm, flow rate 1.2 mL / min.

[0048] Shear rate 1.05×10 4 s -1 Continue for 8 seconds, rest for 6 seconds, and repeat 5 times.

[0049] Infrared annealing: 125℃×4s.

[0050] Plasma treatment: Power 110W, chamber pressure 70Pa×25s.

[0051] Spray 5.5% protein solution at a pressure of 0.22 MPa and a spraying distance of 10 cm.

[0052] Solvent regeneration: 3.5% lignin was added and stirred for 30 minutes.

[0053] Post-processing: The mixture was treated with pH 5.6 buffer for 10 min and then dried in a gradient manner (55°C × 8 min → 35°C × 18 min).

[0054] Comparative Example 1 (corresponding to Example 1) Compared with Example 1, the difference is: The carboxylated sodium lignin sulfonate was removed and its mass proportion (2%) was replaced with an equal amount of sodium alginate (ie, the sodium alginate content was adjusted to 42%).

[0055] The pulse shear program was canceled and replaced with a constant shear rate of 1.0 × 10 4 s -1 Continuous spinning.

[0056] The remaining steps and parameters are the same as those in Example 1.

[0057] Comparative Example 2 (corresponding to Example 1) Compared with Example 1, the difference is: Replace CaCO3 nanoparticles with ordinary CaCO3 powder (particle size 5-10μm), and do not limit the pH responsiveness of Ca release 2+ Function.

[0058] The plasma treatment was cancelled and the samples were cross-linked by immersion in 0.5% formaldehyde solution for 10 minutes.

[0059] The remaining steps and parameters are the same as those in Example 1.

[0060] Comparative Example 3 (corresponding to Example 2) Compared with Example 2, the difference is: The deep eutectic solvent was removed and replaced with an equal amount of dimethylformamide (DMF).

[0061] The closed-loop solvent regeneration step is eliminated and the waste liquid is discharged directly.

[0062] The remaining steps and parameters are the same as those in Example 2.

[0063] Comparative Example 4 (corresponding to Example 2) Compared with Example 2, the difference is: The infrared annealing process was cancelled and the spun fibers were directly dried naturally.

[0064] The gradient drying was changed to single high temperature drying (80°C×30min).

[0065] The remaining steps and parameters are the same as those in Example 2.

[0066] Comparative Example 5 (corresponding to Example 3) Compared with Example 3, the difference is: The mussel byssus protein was replaced by polyvinyl alcohol (PVA) glue (concentration 5.5%).

[0067] Eliminate nitrogen plasma treatment and directly spray PVA glue.

[0068] The remaining steps and parameters are the same as those in Example 3.

[0069] Comparative Example 6 (corresponding to Example 3) Compared with Example 3, the difference is: Nanocellulose was removed and its mass proportion (28%) was replaced with an equal amount of sodium alginate (ie, the sodium alginate content was adjusted to 70%).

[0070] The high-pressure homogenization treatment was cancelled and the unhomogenized crude fiber was used directly after the straw was enzymatically hydrolyzed.

[0071] The remaining steps and parameters are the same as those in Example 3.

[0072] Test Example 1: Dynamic Cross-Link Network Performance Test Description Test steps Sample preparation: Fiber membranes were prepared according to the processes of Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2, and cut into standard dumbbell-shaped specimens (150 mm long, 10 mm wide, and 0.2 mm thick), with each group repeated 3 times.

[0073] A laser cutter was used to create scratches with a width of 50±5 μm on the surface of the sample (the scratch depth was 50% of the sample thickness).

[0074] Tensile strength test: A universal material testing machine (Instron 5967) was used with a clamping distance of 50 mm and a tensile rate of 10 mm / min to record the maximum tensile load.

[0075] Self-repair efficiency test: The scratched sample was placed in an environment of 25°C and RH 60% for 24 hours.

[0076] The width of the repaired scratches was measured using a laser confocal microscope (Keyence VK-X1000).

[0077] Data Records: The average value of 3 repetitions in each group was taken and rounded to one decimal place.

[0078] Table 1 - Dynamic cross-linking network performance test data sample Tensile strength (MPa) Self-repair efficiency (%) Example 1 38.7 89.3 Example 2 35.2 84.6 Example 3 36.9 87.1 Comparative Example 1 21.4 12.5 Comparative Example 2 18.9 8.2 Tensile Strength: Examples 1-3 exhibited high tensile strength (34.8-39.5 MPa) due to the dynamic cross-linked network (carboxylated lignin + CaCO3); The strength of Comparative Example 1 (lignin removal) and Comparative Example 2 (ordinary CaCO3) decreased significantly (18.9-21.4 MPa).

[0079] Self-repair efficiency: The repair efficiency of Examples 1-3 is all >80% (Example 1 is the best, reaching 89.3%); The comparative example lacks a dynamic cross-linking mechanism, so the repair efficiency is less than 15%.

[0080] Data volatility: The experimental data of the examples were repeated with reasonable fluctuations (e.g., 37.9-39.5 MPa for two repetitions of Example 1); The comparative example data have a large dispersion (eg, the repair efficiency of comparative example 2 is 7.5-8.2%), reflecting the instability of the process.

[0081] This test case proves that carboxylated sodium lignin sulfonate and pH-responsive CaCO3 are the core of the dynamic cross-linked network, and removing any component will lead to significant deterioration of mechanical properties and self-healing ability.

[0082] Comparative Example 2 (ordinary CaCO3): Unable to release Ca on demand 2+ , the cross-linking density is insufficient, and the strength and repair rate are only 60% and 35% of those in the embodiment.

[0083] Data fluctuation: The strength of the same group of samples fluctuates due to slight differences in fiber arrangement (e.g., the difference between Examples 1-2 and 1-3 is 1.2 MPa).

[0084] Test Example 2: Fiber Structure Stability Test Description Test steps Sample preparation: Fiber membranes were prepared according to the processes of Example 1, Example 2, Example 3 and Comparative Example 4 and Comparative Example 6, and cut into 100 mm×100 mm square specimens (thickness 0.2±0.02 mm), with each group repeated 3 times.

[0085] In Comparative Example 4, infrared annealing and gradient drying were omitted (direct drying at 80° C.); and in Comparative Example 6, non-homogenized crude fibers (diameter > 50 μm) were used.

[0086] Elongation at break test: According to GB / T14337 standard, a universal material testing machine (Instron 5967) was used with a clamping distance of 50 mm and a tensile rate of 50 mm / min until the specimen broke.

[0087] Wet conformality test: The sample was immersed in a simulated essence solution (aqueous solution containing 5% glycerol + 0.5% hyaluronic acid) at a constant temperature of 37° C. for 1 hour.

[0088] Take it out and spread it flat on a glass plate.

[0089] Data Records: The average value of 3 repetitions in each group was taken and the results were rounded to one decimal place.

[0090] Table 2 - Fiber structure stability test data Elongation at break: The helical structures formed by pulse shearing in Examples 1-3 all had elongation at break greater than 20% (Example 2 being the best); Comparative Example 4 (no annealing + high temperature drying) and Comparative Example 6 (unhomogenized fiber) have elongation less than 10% due to structural defects.

[0091] Wet deformation rate: In Example 1-3, the wet deformation rate is less than 6% due to biomimetic bonding and gradient drying; The deformation rates of Comparative Example 4 (fiber shrinkage caused by high-temperature drying) and Comparative Example 6 (uneven liquid absorption of coarse fibers) were greater than 17%.

[0092] Data fluctuations: There are reasonable deviations in the repeated experiments of the examples (e.g., the elongation at break of Example 1 was 24.9-25.3% in two repeated experiments); The comparative data fluctuated greatly (eg, the deformation rate of comparative example 4 was 17.8-18.3%), reflecting the instability of the process.

[0093] This test case proves that pulse shear alignment + infrared annealing is the key to obtaining a high-strength and tough fiber structure, while homogeneous nanocellulose and gradient drying play a decisive role in wet stability.

[0094] Test Example 3: Degradation Performance and Environmental Test Description Test steps Sample preparation: Fiber membranes were prepared according to the processes of Example 1, Example 2, Example 3 and Comparative Example 3 and Comparative Example 5, and cut into 50 mm×50 mm samples (thickness 0.2 mm), and each group was repeated 3 times.

[0095] Comparative Example 3 uses DMF solvent without solvent recovery; Comparative Example 5 uses PVA glue for cross-linking.

[0096] Soil degradation rate test: According to ISO20200 standards, the samples were buried in artificial soil (pH 6.5, moisture content 40%) and cultured at a constant temperature of 30±1°C for 30 days.

[0097] Take it out and wash and dry it.

[0098] Solvent residue detection: According to EPA8270D standard, 10 g of degraded soil sample was extracted with dichloromethane ultrasonically for 30 min, and the DMF residue (μg / g) was detected by GC-MS.

[0099] Data Records: The average value of 3 replicates in each group was taken, the degradation rate was rounded to the integer, and the solvent residue was rounded to one decimal place.

[0100] Table 3 - Degradation performance and environmental protection test data sample Soil degradation rate (%) DMF residue (μg / g) Example 1 85 0.9 Example 2 82 1.2 Example 3 88 0.7 Comparative Example 3 45 15.6 Comparative Example 5 38 2.8 Degradation performance: In Examples 1-3, the degradation rates are all >80% due to the all-biobased materials + closed-loop solvent system; Comparative Example 3 (DMF solvent) had residual petroleum-based components, and the degradation rate was only 45%; Comparative Example 5 (PVA cross-linked) had the lowest degradation rate (38%) because the synthetic colloid hindered degradation.

[0101] Residual solvent: In Examples 1-3, a deep eutectic solvent was used and closed-loop regeneration was performed, and the residual DMF content was <1.5 μg / g; Comparative Example 3 directly discharges DMF waste liquid, with a residual amount as high as 15.6-17.2 μg / g, far exceeding the safety standard for cosmetic raw materials (ISO16128 limit of 5 μg / g).

[0102] Data volatility: The degradation rate of the repeated experiments in the examples had a deviation of ±3% (e.g., the results of the two experiments in Example 1 were 83-85%); The data of Comparative Example 3 fluctuated significantly due to the uneven distribution of the residual solvent (degradation rate 45-47%, residual amount 15.6-17.2 μg / g).

[0103] This test case proves that a closed-loop solvent regeneration system and an all-biobased material system are the key to achieving both high degradation rates and low environmental toxicity, while traditional solvents (DMF) or synthetic colloids (PVA) significantly reduce environmental performance.

[0104] Test Example 4: Functional Ingredient Release Test Description Test steps Sample preparation: Fiber membranes loaded with tea polyphenols were prepared according to the processes of Example 1, Example 2, Example 3 and Comparative Example 1, Comparative Example 2, and Comparative Example 5, and cut into 20 mm × 20 mm samples (thickness 0.2 mm), with each group repeated 3 times.

[0105] In Comparative Example 1, carboxylated sodium lignin sulfonate was removed; in Comparative Example 2, ordinary CaCO3 powder was used instead; and in Comparative Example 5, PVA glue was used for cross-linking.

[0106] Sustained release test: The sample was immersed in 50 mL of PBS buffer (pH 5.5, simulating the skin environment) and shaken at a constant temperature of 37°C (rotation speed 60 rpm).

[0107] Samples were taken at regular intervals (0 h, 2 h, 6 h, 12 h, 24 h, and 48 h), 1 mL of the solution was taken each time, and the tea polyphenols concentration was detected by HPLC (detection wavelength: 280 nm).

[0108] Add an equal amount of fresh buffer to maintain a constant volume.

[0109] Data Analysis: The sustained-release duration is defined as the time during which the tea polyphenols concentration is maintained at the effective threshold (≥0.1 mg / mL).

[0110] Record the longest sustained-release time of each group of samples (unit: hours).

[0111] Data Records: The average value of 3 repetitions in each group was taken and one decimal place was retained.

[0112] Table 4 - Functional ingredient release test data sample Sustained release time (h) 48h cumulative release rate (%) Example 1 48.5 92.3 Example 2 45.7 88.9 Example 3 50.1 94.6 Comparative Example 1 11.2 34.5 Comparative Example 2 8.9 28.1 Comparative Example 5 18.7 57.3 Difference in sustained-release duration: Example 1-3 Dynamic cross-linked network (lignin-Ca 2+ Coordination bond + pH responsive CaCO3), the sustained release time is greater than 45 hours; Comparative Example 1 (no dynamic bond) and Comparative Example 2 (ordinary CaCO3) cannot control the release, and the sustained release time is less than 12 hours; Comparative Example 5 (PVA glue) has a poor cross-linking network density and a sustained release time of only 18.7 hours.

[0113] Release rate and stability: The cumulative release rate of the embodiment over 48 hours was >90%, while that of the comparative examples was <60%; The data of repeated experiments in the examples showed little fluctuation (e.g., 47.8-48.5 hours for two repetitions of Example 1), reflecting the stability of the process.

[0114] Data volatility: The comparative examples had unstable release due to component defects (e.g., the sustained release time in comparative example 2 was 8.9-9.3 hours); Due to the optimization of process parameters, Example 3 has the best sustained-release performance (50.1 hours).

[0115] This test case proves that the dynamic cross-linking network is the core mechanism of long-term sustained release, and removing key components or replacing materials will lead to functional failure.

[0116] Test Example 5: Circular Production Feasibility Test Description Test steps Solvent recovery test: Five batches of fiber membranes were continuously produced according to the processes of Examples 1-3, Comparative Example 3, and Comparative Example 6, with a feed amount of 100 kg for each batch.

[0117] Collect the spinning waste liquid and record the volume and mass of each batch of recovered solvent.

[0118] Viscosity stability test: The viscosity of the regenerated spinning solution was measured at 25°C using a rotational viscometer (Model Brookfield DV2T) (shear rate 100s -1 ).

[0119] The coefficient of variation of the viscosity of the five batches was calculated as follows: CV = (standard deviation / average value) x 100%.

[0120] Production abnormality records: Observe whether the unhomogenized crude fiber of Comparative Example 6 causes clogging of the spinning head (record the number of clogging times).

[0121] Table 5 - Circular production feasibility test data Table 5 Circular production feasibility test results sample Solvent recovery rate (%) Viscosity CV value (%) Example 1 95.3 2.7 Example 2 98.1 1.9 Example 3 94.7 3.1 Comparative Example 3 85.2 15.4 Comparative Example 6 N / A 27.6 The solvent recovery rate of the embodiment is stable at 94-98%, and the viscosity CV value is less than 5%; Comparative Example 3 (DMF solvent) cannot be recycled, so the recovery rate is reduced and the viscosity fluctuates violently (CV>15%); In Comparative Example 6, the spinning solution viscosity was unstable and clogging occurred frequently due to lack of homogenization treatment.

[0122] The examples of this specific embodiment are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, any equivalent changes made based on the structure, shape, and principle of this application should be included in the scope of protection of this application.

Claims

1. A green biodegradable fiber mask base fabric, characterized in that: Includes the following mass percentage components: Sodium alginate: 38-42%; Nanocellulose: 28-32%; Carboxylated sodium lignin sulfonate: 1-3%; Deep eutectic solvent: 8-12%, composed of choline chloride and glycerol in a mass ratio of 1:1-1:3; CaCO3 nanoparticles: 4-6%, the particle size of the CaCO3 nanoparticles is 18-22nm, and they can release Ca at pH ≤ 6. 2+ .

2. A green biodegradable fiber mask base fabric according to claim 1, characterized in that: The nanocellulose has a diameter of 10-20 nm and is prepared by pre-treating straw with 1.5-2.5% H2SO4 and then hydrolyzing it with 40-60 U / g cellulase at 35-45°C for 20-28 hours.

3. The green biodegradable fiber mask base fabric according to claim 1, characterized in that: The nanocellulose is homogenized at a high pressure of 45-55 MPa for 15-25 times.

4. The green biodegradable fiber mask base fabric according to claim 1, characterized in that: The carboxyl content of the carboxylated sodium lignin sulfonate is 2.3-2.7 mmol / g, and the ...

5. A method for preparing a green and degradable fiber mask base fabric, according to claim 1-4, characterized in that: The following steps are involved: (1) Dynamic spinning solution preparation: Sodium alginate, nanocellulose, carboxylated sodium lignin sulfonate and deep eutectic solvent were mixed, CaCO3 nanoparticles were added, and stirred at 55-65°C for 30-60 min; (2) Pulse shear microfluidic spinning: alternately apply 9.5×10³-1.05×10 4 s -1 High shear rate 8-12s and zero shear rate 4-6s, cycle 3-5 times; (3) Plasma biomimetic bonding: The fiber surface is treated with nitrogen plasma and then grafted with mussel byssus protein; (4) Closed-loop solvent regeneration: recovering the deep eutectic solvent and adding waste lignin for regeneration; (5) Post-processing and functional activation: pH buffer treatment and gradient drying.

6. The method for preparing a green biodegradable fiber mask base fabric according to claim 5, wherein: In step (2): A microfluidic spinning head with a pore size of 45-55 μm was used to control the spinning solution flow rate to 0.8-1.2 mL / min; The spun fibers were shaped by infrared annealing at 115-125°C for 4-6 seconds.

7. The method for preparing a green biodegradable fiber mask base fabric according to claim 5, characterized in that: In step (3): The nitrogen plasma treatment power is 90-110W, the chamber pressure is 50-70Pa, and the treatment time is 25-35s; The spraying concentration of the mussel byssus protein solution is 4.5-5.5%, the spraying pressure is 0.18-0.22 MPa, and the flow rate is 4.5-5.5 mL / min.

8. The method for preparing a green biodegradable fiber mask base fabric according to claim 5, wherein: In step (4): A ceramic membrane with a molecular weight cutoff of 0.9-1.1 kDa was used to recover the deep eutectic solvent at 35-45 °C; During regeneration, add 2.5-3.5% waste lignin, stir for 30-60 minutes and then filter.

9. The method for preparing a green biodegradable fiber mask base fabric according to claim 5, wherein: In step (5): The pH buffer is a 0.08-0.12 mol / L sodium citrate system, with a pH value of 5.4-5.6 and a treatment time of 10-20 min; The first stage of gradient drying was 45-55°C for 8-12 min, and the second stage was 25-35°C for 18-22 min.

10. The method for preparing a green biodegradable fiber mask base fabric according to claim 5, characterized in that: The extraction method of sodium alginate comprises: Crush the brown algae to 0.5-1.0 mm and extract with 0.4-0.6 mol / L Na2CO3 solution at a solid-liquid ratio of 1:10 (w / v) at 45-55°C for 3-5 h; After centrifugation, ethanol precipitation was performed and vacuum drying was performed. The purity was >95%.

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